Automatic gas powered gun

ABSTRACT

A gas powered gun is disclosed for repeated discharge of projectiles. The gun includes a barrel adapted to receive a projectile from a magazine, a pressure chamber adapted to communicate with a compressed gas cartridge fitted to the gun, an open-close valve for exhausting compressed gas from said chamber to discharge a projectile in the barrel, and a hammer arranged to actuate the open-close valve. The gun further includes a chamber for collecting partly expanded compressed gas after the gas has been used to discharge the projectile, a piston arranged in a housing and being mechanically connected to the hammer, and a channel for directing the partly expanded gas into the housing, so that the gas will force said piston to move, thereby bringing the hammer to a ready-for-fire-position.

FIELD OF THE INVENTION

The present invention relates to a gas powered gun for repeateddischarge of projectiles, comprising a barrel adapted to receive aprojectile from a magazine, a pressure chamber adapted to communicatewith a compressed gas cartridge fitted to the gun, an open-close valvefor exhausting compressed gas from said chamber to discharge aprojectile in the barrel, and a hammer arranged to actuate saidopen-close valve. More specifically, the invention relates to automaticreloading of such a gun, to enable repeated firing.

BACKGROUND OF THE INVENTION

In a conventional gas powered gun, the user manually reloads the gunafter firing, by moving a handle backwards and forwards. This motionbrings the hammer back to a loaded position, while at the same timebrings a feeder pin back to allow for a new bullet to be inserted, andthen forward, to feed this bullet into the barrel. In case of a gunprovided with a magazine, the back-forward motion can be consecutive,otherwise it will be a two-step motion, with the insertion of a bullettaking place between the back and forward movements.

There are examples of automatic gas powered guns, for example asdisclosed in U.S. Pat. No. 6,497,229. In such a gun, a change valve isused to direct compressed air from the cartridge alternatingly through afirst opening, to discharge the bullet, and through a second opening toreload the gun. A drawback with this type of solution is that theefficiency of the guns is reduced, as part of the compressed air in thecartridge will be used to reload the gun. A further drawback is thatcompressed gas from the cartridge will actuate the reload before thebullet has left the gun. The recoil from the reload will therefore risklowering the precision.

GENERAL DISCLOSURE OF THE INVENTION

It is therefore an object of the present invention to provide anautomatic or semi-automatic gas powered gun, without reducing theefficiency of the gun.

This and other objects are achieved by a gun of the kind mentionedabove, further comprising a chamber for collecting partly expandedcompressed gas after said gas has been used to discharge saidprojectile, a piston arranged in a housing and being mechanicallyconnected to said hammer, and a channel for directing said partlyexpanded gas into said housing, so that said gas will force said pistonto move, thereby bringing said hammer to a ready-for-fire-position.

The invention is based on the insight that the gas that has been used todischarge the bullet is only partly expanded, and thus does stillcontain a considerable amount of energy. It is this energy thattypically is transformed into sound waves, to result in a crack of thegun. According to the invention, this energy is instead used to reloadthe gun. As the energy in the partly expanded gas is extracted after thebullet has been discharged, the efficiency of the gun is not reduced.However, the noise of the gun is reduced.

Preferably, the partly expanded gas is collected only after the bullethas left the gun, and as a consequence, the recoil from the reload willnot affect the precision of the gun.

The piston can be biased against the pressure of the gas by a biasingmeans, so that, after being forced back by the pressure of the partlyexpanded gas, the piston returns to its initial position by the force ofsaid biasing means. This completes the reload action, which is thusfully automatic. The biasing means can be a return spring.

The piston is preferably connected to the hammer uni-directionally, sothat the hammer, after being brought to a ready-to-fire-position by thepiston, can be held in this position by a catch. When the piston isreturned by the biasing means, the hammer will thus be held in place bythe catch.

The gun can further comprise a feeder pin adapted to feed a projectilefrom the magazine into the barrel, and the piston can then bemechanically connected also to the feeder pin, so that, when said gasforces said piston to move, the feeder pin will be returned to a reloadposition. By use of a feeder pin, the insertion of a consecutive bulletis facilitated, and automated by the connection to the piston. In thiscase, the biasing means, e.g. the return spring, may be arranged incontact with the feeder pin, and the movement of the feeder pin and thepiston are preferably synchronized in the longitudinal direction of thegun. In other words, when the piston moves, the feeder pin moves with itand vice versa.

According to one embodiment, the piston and the housing are alignedessentially in parallel with said barrel, for example underneath thebarrel. According to another embodiment, the piston is arrangedcoaxially around the barrel.

BRIEF DESCRIPTION OF THE DRAWINGS

This and other aspects of the present invention will now be described inmore detail, with reference to the appended drawings showing twocurrently preferred embodiments of the invention.

FIG. 1 is a side view of a gun according to a first embodiment of thepresent invention, in a ready-to-fire-condition.

FIG. 2 is a side view, of the gun in FIG. 1, in a condition immediatelyafter firing.

FIG. 3 is a perspective view of the gun in FIG. 1, in a condition duringautomatic reloading.

FIGS. 4 a-c show a sequence after the gun of an embodiment has beenfired.

FIG. 5 is a gun according to another embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows an air gun according to a first embodiment of theinvention. The gun 1 is of the kind where a cartridge 2 of compressedair or other gas is fitted to the body 3 of the gun. Typically, thecartridge 2 is fitted in the back, and may be enclosed in the stock ofthe gun (not shown/see FIG. 3). The gun further comprises a barrel 4,and a feeder pin 5 slidably arranged in a housing 6 behind the barrel 4,biased in the forward direction by a biasing means, here a return spring7. In a space between barrel and the feeder pin is fitted a magazine 8for providing projectiles e.g. in the firm of diabolo bullets 9. Themagazine can for example be of the kind disclosed in EP 341090. Thefeeder pin 5 is arranged to be slid back, thereby allowing a bullet 9 tobe provided from the magazine 8, and then to be slid forward, therebyfeeding the bullet 9 a into a firing position in the barrel 4.

The gun further comprises an open-close valve 10 for allowing passage ofcompressed air from the cartridge 2 to a space 11 immediately behind abullet 9 a in the barrel 4, and a sliding hammer 12 for activating thevalve 10 at the moment of firing. The hammer 12 is biased towards thevalve 10 by suitable biasing means, here a biasing spring 13, and isheld in a loaded position, against the force of the biasing spring, by acatch 14 engaging an abutment in the hammer, here an annular flange 15.A trigger 16 is arranged to actuate the catch 14 in order to release thehammer 12.

In the illustrated example, the catch 14 is pivotable around a point Abehind the annular flange 15, and biased by a spring 17 out ofengagement with the hammer. The catch 14 is kept in engagement with theflange 15 by a support surface 18 of the trigger 16. The trigger 16 isarranged to be pivoted around an axis B by action of the user, in orderto slightly dislocate the support surface 18, thereby allowing the catch14 to be forced by the spring 17 away from the hammer 12 and release it.The rear end of the flange 15, and the upper side of the catch 14 arefurther formed such that, when the hammer 15 is brought back to itsloaded position, the flange 15 engages the catch 14 and the catch 14 isforced into its locking position, against the action of the spring 17.Many other solutions of trigger-stopper-cooperation are of coursepossible, and can implemented by the skilled person.

In the illustrated example, the open-close valve 10 has a main body 20oriented essentially in the longitudinal direction of the gun, andending with a valve head 21 adapted to cooperate with an opening of apressure chamber 23 in front of the valve 10, the opening thus acting asa valve seat 22. A channel 24 is connected via suitable valve means (notshown) to the fitting 25 of the compressed air cartridge 2, and extendsto the chamber 23, thus providing high pressure to the chamber. Thepressure keeps the valve head 21 in place against the valve seat 22,thus effectively sealing the chamber 23. If required, or if consideredadvantageous, the valve head 21 can additionally be biased against theseat by a biasing spring (not shown). Another channel 26 connects aspace behind the valve seat 22 with the space 11 behind a bullet 9 a inthe barrel. Many other solutions for an open-close valve 10, to beactuated by the hammer 12, are possible.

A follower 27 is attached to the feeder pin 5, and arranged to engagethe hammer 12 and to move it backwards, against the force of the biasingspring 13. The engagement is unidirectional, so that when the feeder pin5 and follower 27 is subsequently returned forward, the hammer 12remains in its loaded position, held in place by the catch 14. In theillustrated example, the follower 27 is fixedly attached to the feederpin, and the back side of the follower 27 engages the annular flange 15of the hammer 12.

FIG. 1 shows the gun in a ready-for-fire-position. In this condition,the feeder pin 5 has been slid into the barrel 4, and fed a bullet 9 ainto the firing position. The hammer 12 is in its loaded position, heldin place by the catch, against the force of the biasing spring 13, andthe valve 10 seals the chamber 23 which is filled with high pressure airfrom the cartridge 2.

FIG. 2 shows what happens when the trigger is pulled. The trigger 16pivots slightly, so that the catch 14 is allowed to disengage the hammer12. The hammer 12 is thus released and forced by the spring 13 intocontact with the rear portion of the main body 20 of the open-closevalve 10. This briefly brings the valve head 21 out of sealing contactwith the valve seat 22, to thereby allow an exhaust of air through thechannel 26 to the space 11 behind the bullet 9 a. As soon as the hammerhas lost enough of its momentum, the valve head 21 is again pressedagainst the valve seat 22 to seal the chamber 23, which is again filledwith compressed air. The compressed air exhausted into the space 11behind the bullet 9 a expands, to thereby discharge the bullet 9 athrough the barrel 4, thus firing the gun.

In a conventional, single-fire air gun, each firing sequence is followedby a manual reload using a handle 28 (see FIG. 3), connected to thefollower 27. During such a reload motion, the follower is first movedback, thereby moving the feeder pin 5 back, to allow for a new bullet 9to be provided by the magazine 8. The follower 27 also brings the hammer12 back to be locked in the loaded position by the catch 14. Then, thehandle 28 is moved forward, thereby moving the feeder pin 5 forward, tofeed the bullet 9 a into the barrel, as described above. The handle 28may be fixed in the back position by a safety catch (not shown), inorder to secure the gun, for example during insertion of a new magazine.According to the present invention, the reload procedure is insteadperformed automatically.

FIG. 3 shows how the gun, for this purpose, is further provided with achamber 30 for collecting partly expanded air that has been used todischarge the bullet 9 a. In the illustrated example, this chamber 30 isarranged at the end of the barrel, in a similar way as a silencer isfitted. The barrel 4 extends into one side of the chamber 30, and in theother side is fitted a plug 31 with a muzzle 32. The gun is alsoprovided with a cylinder housing 33, here located below and along thebarrel 4. The interior of the cylinder housing is connected to thechamber 30 by means of a channel 34. In the housing 33 is arranged thefront end 35 a of a piston 35. The rear end of the piston 35, whichextends outside the housing 33, is mechanically connected to thefollower 27 so as to transfer any movement of the piston 35 to thefollower 27.

In the illustrated example, the channel is a tube 34, attached with oneend to an opening 36 of the chamber 30, and the other end to acylindrical portion 37 of the body 3 of the gun, which portion housesthe pressure chamber 23. The housing 33 is in its front end secured tothe tube 34 in an air-tight manner, here by means of a locking screw anda suitable seal (not shown). Inside the housing 33, the tube is providedwith holes 38, allowing exhaust of gas into the housing 33. The piston35 is formed as a cylinder, surrounding the cylindrical portion 37, andis in its front end 35 a sealingly arranged against the tube 34 as wellas the housing 33. In a preferred embodiment the piston is of plastic orother equivalent light weight material, and the sealing is achieved bypiston rings of the same material. In the rear end of the cylindricalpiston 35 is attached an annular fitting 39, e.g. made of aluminum, towhich one end of a strut 40 of suitable form is attached. The other endof the strut 40 is attached to the follower 27. In the shown example,the strut is double, i.e. the follower 27 is connected to the piston 35on both sides of the gun.

FIG. 4 a-c show a sequence after the gun has been fired.

First, in FIG. 4 a, the shot goes off, and the bullet 9 a is discharged.The effect of the chamber 30 is similar to that of a silencer. When aburst of air leaves the barrel it expands quickly, but is contained bythe chamber 30 and is prevented from escaping and causing a crack.Instead, the partly expanded air will enter the opening 36, and followthe channel 34 to the housing 33. Here, the burst will force the piston35 backwards as indicated by arrow C.

As shown in FIG. 4 b, the piston 35 will be pushed to a withdrawnposition. Through the mechanical connection to the follower 27, here bymeans of the strut 40, the movement will also move the hammer 12 andfeeder pin 5 back. Any remaining energy in the burst of air will beabsorbed by the walls in the chamber 30, channel 34 and housing 33, andthe remaining pressure will eventually be let out through the muzzle 32.

As shown in FIG. 4 b, when the pressure on the piston has been reduced,the return spring 7 will returned the feeder pin 5 and the piston 35 totheir initial, forward positions, thus completing the reload motion. Thegun is thereby essentially returned to the ready-to-fire-position shownin FIG. 1. It should be noted that, as the piston and feeder pin areconnected to each other and move together, the return spring can equallywell be arranged to engage the piston 35, for example in the housing 33.

Also shown in FIG. 3, 4 b and 4 c is a blocking mechanism 41, arrangedto prevent the repeated firing of multiple shots by a single pull of thetrigger. The mechanism comprises a depressing pin 42 adapted to pivotaround an axis D. In a first position the pin 42 is located behind thetrigger 16, without engaging the trigger, while in a second position,the pin 42 is adapted to cooperate with the rear portion 43 of thetrigger 16, to press the trigger into a position where it supports thecatch 14, preventing release of the hammer 12. The pin is actuated by alever 44 adapted to be pushed back by the strut 40, thereby moving thepin into its second position.

The pin is biased toward the first position, e.g. by a biasing spring(not shown). However, the rear portion 43 of the trigger has a groove 45formed to receive the pin 42, and to hold it in place against the actionof the biasing spring, until any pressure on the trigger is removed.

In use, when the user presses the trigger and fires the gun, the piston35 will be forced back, so that the strut 40 brings the feeder pin 5 andhammer 12 back, as described above with reference to FIG. 4 b. At thesame time, the strut 40 will abut the lever 44, and push it back, sothat the depressing pin 42 is moved to its second position and engagethe trigger 16. Due to the leverage of the lever, the force on thetrigger 16 will be significant, and the trigger 16 will be returned toits original position against any pressure applied by the user (see FIG.4 b, lower part). Note that the hammer 12 on its way back engages thecatch 14, to force it towards the hammer 12, out of engagement with thetrigger 16. The blocking mechanism 41 is adapted to return the trigger16 at the precise moment during which the catch 14 is pushed back, sothat the supporting surface 18 of the trigger can return to support thecatch 14, and prevent it from releasing the hammer 12. Further, as longas the user maintains a pressure on the trigger 16, the pin 42 will beheld firm in the groove 45, preventing the subsequent firing. Only whenthe user releases the pressure on the trigger 16 will the biasing springmove the blocking mechanism 41 to its first position, thus againallowing the trigger to be pulled by the user. In this way, the pin andlever ensure a single-shot action of the gun, which is then a so calledsemi-automatic gun.

The blocking mechanism 41 is optional, and does not limit the presentinvention. Without it, the gun will be a fully automatic gun, allowingrapid fire of subsequent shots.

According to a second embodiment of the invention, shown in FIG. 5, thepiston 135 is arranged coaxially with the barrel 104. A cover 101 isarranged coaxially outside the piston 135, to form a compartment 102 infront of the piston 135. A perforated annular member 103 is fitted onthe barrel 4 in the cover 101, thereby dividing the compartment 102 intoa chamber 130 and a housing 133. In this embodiment, there is no needfor any channel between the chamber 130 and the housing 133. Instead,the burst of air having discharged the bullet will flow through theperforations in the member 103 into the housing 133 and push the pistonback. Remaining details of the gun, including the connection between thepiston 135 and the follower can be designed similarly as in the firstembodiment.

1. A gas powered gun for repeated discharge of projectiles, comprising:a barrel adapted to receive a projectile from a magazine, a pressurechamber adapted to communicate with a compressed gas cartridge fitted tothe gun, an open-close valve for exhausting compressed gas from saidchamber to discharge a projectile in the barrel, and a hammer arrangedto actuate said open-close valve, a chamber for collecting partlyexpanded compressed gas after said gas has been used to discharge saidprojectile, a piston arranged in a housing and being mechanicallyconnected to said hammer, and a channel for directing said partlyexpanded gas into said housing, so that said gas will force said pistonto move, thereby bringing said hammer to a ready-to-fire-position.
 2. Agas powered gun according to claim 1, wherein said piston is biasedagainst the pressure of said gas by a biasing device, so that, afterbeing forced back by the pressure of the partly expanded gas, the pistonreturns to its initial position by the force of said biasing device. 3.A gas powered gun according to claim 1, wherein the piston is connectedto the hammer uni-directionally, so that the hammer, after being broughtto a ready-to-fire-position by the piston, is held in this position by acatch.
 4. A gas powered gun according to claim 1, wherein said gunfurther comprises a feeder pin adapted to feed a projectile from saidmagazine into the barrel, and wherein said piston is also mechanicallyconnected to said feeder pin, so that, when said gas forces said pistonto move, said feeder pin will be returned to a reload position.
 5. A gaspowered gun according to claim 4, wherein said piston is biased againstthe pressure of said gas by a biasing device, so that, after beingforced back by the pressure of the partly expanded gas, the pistonreturns to its initial position by the force of said biasing device andwherein said biasing device is arranged in contact with said feeder pin.6. A gas powered gun according to claim 4, wherein said piston ismechanically connected to the feeder pin in such a way that the movementof the feeder pin and the piston, in the longitudinal direction of thegun, are synchronized.
 7. A gas powered gun according to claim 1,wherein said piston and said housing are aligned essentially in parallelwith said barrel.
 8. A gas powered gun according to claim 7, whereinsaid piston is arranged coaxially around said barrel.